1. Field of the Invention:
The present invention relates generally to electric propulsion systems for use in maneuvering boats and, more particularly, to electric propulsion systems having retractable propulsion units.
2. Discussion of the Prior Art:
Electric trolling motors have been widely used on conventional fishing boats such as bass boats. Conventional electric trolling motors have a number of disadvantages, especially when used in applications other than for small fishing boats. Many boats lack a suitable deck or transom mounting area for use with a convention trolling motor. Sailboats and smaller boats often do not have appropriate areas to mount a trolling motor. Bow mounts, the most popular configuration for trolling motors, require expensive mounting brackets and remote controls in order to facilitate use. Typically, the motors are hung off the bow in a highly exposed location. The long, exposed shafts and the mounting brackets for the motors are highly stressed and often break. Conventional trolling motors are usually in the way, and do not present a clean, attractive appearance. Often, sailboats are operated with electric motors, some of which are specifically designed for salt water use. Such motors may remain submerged in salt water and typically last for eight to twelve months before failure. This short life makes it desirable to have a motor which can be removed from the corrosive influences of salt water when not in use.
Previous attempts have been made to mount trolling or bow thruster-type propulsion units through the hull of a boat. Such attempts have required large openings in the hull, which may compromise the boat""s structural integrity, and are difficult and expensive to install. Cleaning fouled propulsion units is also difficult with prior arrangements.
Accordingly, it is a primary object of the present invention to overcome the aforementioned disadvantages of prior electric propulsion systems for boats.
Another object of the present invention is to simplify retraction of a propulsion unit of an electric propulsion system in a boat.
An additional object of the present invention is to facilitate cleaning of a propulsion unit of an electric propulsion system in a boat.
A further object of the present invention is to extend the life of electric propulsion systems for boats.
A still further object of the present invention is to allow an electric drive motor used to drive a propulsion unit in a boat to be removed from the water when not in use.
It is also an object of the present invention to reduce the size of an opening needed in the hull of a boat to mount an electric propulsion system.
The present invention has as another object to permit an extended propulsion unit of an electric propulsion system in a boat to flex upon impacting an object.
Yet a further object of the present invention is to facilitate proper orientation of a propulsion unit of an electric propulsion system in a boat to permit retraction into a support tube.
Additionally, it is an object of the present invention to facilitate steering of a propulsion unit of an electric propulsion system in a boat.
Some of the advantages of present invention are that the drive unit and the propulsion unit for the electric propulsion systems can be removed completely, from inside the boat, as a unitary assembly with no loose parts, the propulsion unit can be completely hidden in a retracted position, operation of the propulsion unit can be controlled from various locations on the boat and in various ways including via a handle, a foot control, an electric control panel, a wireless remote and/or a passenger seat, the reliability and ease of servicing the electric drive motor are enhanced, various propulsion units can be used interchangeably in the electric propulsion systems, various electric propulsion systems, motors can be used interchangeably in the drive the propulsion units can be extended and retracted automatically or manually, the electric propulsion systems can be used on a variety of boat types, and the electric propulsion systems can be used for auxiliary power, as a bow thruster, or for primary propulsion.
These and other objects, advantages and benefits are realized with the present invention as generally characterized in an electric propulsion system comprising a first tube extending between an opening in a hull of a boat and an opening in a surface of the boat spaced from the hull. The openings are in longitudinal alignment, with an upper end of the first tube adjacent the opening in the surface and a lower end of the first tube adjacent the opening in the hull. The first tube is fixedly secured to the hull and remains in place. A second tube is concentrically disposed in the first tube and is longitudinally movable relative to the first tube for withdrawal therefrom via the opening in the surface. A drive motor is disposed in the second tube, which may be a steering tube, and is removable from the first tube as the second tube is removed. The drive motor is longitudinally movable relative to the second tube between upper and lower positions. The drive motor has a rotatable output shaft coupled with a propulsion unit. The propulsion unit is longitudinally movable with the drive motor between retracted and extended positions. When the drive motor is in the upper position, the propulsion unit is in the retracted position wherein the propulsion unit is disposed within the second tube. When the drive motor is in the lower position, the propulsion unit is in the extended position wherein the propulsion unit is disposed externally of the hull and the lower end of the support tube. The propulsion unit includes a blade assembly rotated by the output shaft of the drive motor to provide propulsion. An actuating member within the second tube is coupled with the drive motor and is used to move the drive motor between the upper and lower positions thereby moving the propulsion unit between the retracted and extended positions. Where the second tube is a steering tube, the second tube is rotatable relative to the first tube, and the drive motor is rotated correspondingly with the second tube to steer or change the directional orientation of the propulsion unit. The blade assembly may have a first rotational position wherein the blade assembly presents a configuration too large to be accommodated in the second tube. In this case, the blade assembly automatically assumes a second rotational position, of a size to be accommodated in the second tube, when not being driven by the output shaft. The blade assembly may have a first configuration too large to be accommodated in the second tube, with the blade assembly being moved automatically to a second configuration, of a size to be accommodated in the second tube, in response to retraction of the propulsion unit into the second tube. The drive motor may be disposed externally of the hull and the lower end of the first tube in the lower position, and may be in an angularly offset orientation with the second tube when disposed in the lower position externally of the hull. The drive motor, in the latter case, is automatically moved to a longitudinally aligned orientation with the second tube in response to retraction of the drive motor into the second tube.
These and other objects, advantages and benefits of the present invention will become apparent upon consideration of the following detailed description of preferred embodiments thereof, particularly when taken in conjunction with the accompanying ram drawings, wherein like reference numerals and various figures are utilized to designate like or similar components.